High-temperature plastic deformation of Y2O3-stabilized ZrO2single crystals. II. Electron microscopy studies of dislocation substructures

Dislocation substructures in Y2O3-stabilized ZrO2 single crystals, oriented for single slip on {001}<110> and deformed at 1400[ddot]C, have been studied. The high linear work-hardening rate past microyielding is due to the accumulation of a large number of edge dipoles produced by dragging of jogs on screw dislocations, and their break-up by climb or cross-slip into prismatic loops. The apparent macroscopic yield drop is due to activation of secondary slip on {111}, which thereafter dominates deformation because interaction of primary and secondary dislocations produces jogs on primary dislocations, but kinks on secondary dislocations.